people = 30
cars = 40
buses = 15

if cars > people
  puts "we should take the cars."
elsif cars < people 
  puts "We should not take the cars."
else 
  puts "We can't decide."
end

if buses > cars
  puts "That's too many buses."
elsif buses < cars
  puts "Maybe we could take the buses."
else
  puts "We still can't decide."
end

if people > buses
  puts "Alright, let's just take the buses."
else
  puts "Fine, let's stay home then."
end
# if 和else的运用，在前面是单个单个条件的进行列出，如果要达到一个目标有多重条件的时候就会用多重条件限定，分支条件使用elsif , 除开if 和elsif 外的所有其他情况使用else， 既然是所有情况，那么else后面就不应该再接其他的限制性条件
